1. Field of the Invention
The present invention relates to a fallboard arrangement for a keyboard instrument, which is applied to a keyboard instrument, such as an electronic piano, the keyboard instrument having a fallboard configured to pivotally move to open and close a performance section including a keyboard, and an opening and closing device for a fallboard, which is configured to open and close a fallboard attached to a musical instrument body in a manner pivotally movable between a fully-open position for opening a keyboard and a fully-closed position for closing the keyboard.
2. Description of the Related Art
Conventionally, there has been known a fallboard arrangement of this type disclosed e.g. in Japanese Laid-Open Patent Publication (Kokai) No. 2003-177738 filed by the present applicant. The fallboard arrangement, which is applied e.g. to an upright piano, includes a fallboard back section, and a fallboard pivotally connected to a front end of the fallboard back section via a hinge to open and close a keyboard. Note that the fallboard arrangement is provided with a rotary dumper and a link mechanism connecting between the rotary dumper and the fallboard, so as to brake the pivotal motion of the fallboard in the closing direction using the rotary dumper and the link mechanism.
FIG. 9A shows the above-mentioned conventional fallboard arrangement. As shown in FIG. 9A, in the fallboard arrangement 41, the hinge, denoted by a reference numeral 44, is mounted in a manner sandwiched between a front end face (left end face as viewed in FIG. 9A) of the fallboard back section, denoted by a reference numeral 42, and a rear end face (right end face as viewed in FIG. 9A) of the fallboard, denoted by a reference numeral 43. As shown in FIG. 9B, the hinge 44 is comprised of a fallboard back section-side fixed plate 45 and a fallboard-side fixed plate 46 each having one end (upper end as viewed in FIG. 9B) thereof formed with an associated one of hollow cylindrical connection tubes 45a and 46a, and a connection shaft 47 inserted through the connection tubes 45a and 46a for connection of the two fixed plates 45 and 46. The fallboard back section-side fixed plate 45 of the hinge 44 is rigidly secured to the front end face, denoted by a reference numeral 42a, of the fallboard back section 42 with screws 48, and the fallboard-side fixed plate, denoted by a reference numeral 46, is rigidly secured to the rear end face, denoted by a reference numeral 43a, of the fallboard 43 with screws (hereinafter referred to as “the long screws”) 49 which are longer than the fallboard back section-side screws 48.
More specifically, as for the fallboard-side fixed plate 46 of the hinge 44, the long screws 49 and a metal plate 50 having screw holes 50a are used to securely fix the fixed plate 46 to the fallboard 43. Further more specifically, the metal plate 50 is embedded in the fallboard 43 at a predetermined location, and holes 43b are formed in the fallboard 43 in a manner extending from the rear end face 43a of the fallboard 43 to the metal plate 50. Then, the long screws 49 are screwed into the screw holes 50a of the metal plate 50 from the side of the rear end face 43a of the fallboard 43 via the holes 43b, respectively. This causes the fallboard 43 to be fastened in a state held between the fallboard-side fixed plate 46 of the hinge 44 and the metal plate 50, whereby the fallboard 43 is securely connected to the fallboard back section 42 via the hinge 44. When the front end of the fallboard 43 is lifted, the fallboard 43 is pivotally moved about the hinge 44, as shown in FIG. 10, to be opened.
In the above-described fallboard arrangement, when the fallboard 43 is closed, the upper surface of the fallboard 43 and that of the fallboard back section 42 become horizontally flush with each other. In this case, however, the connection shaft 47 of the hinge 44 and the connection tubes 45a and 46a of the respective fixed plates 45 and 46 connected by the connection shaft 47 project upward from between the fallboard 43 and fallboard back section 42, and hence a good appearance cannot be obtained. Further, when a user of the piano wants to open e.g. a music book or a notebook on the fallboard 43 in a closed state thereof and write something on it, the portion of the hinge 44 projecting upward can become an obstacle.
As the opening and closing device for a fallboard of the above-mentioned type, there has conventionally been known one disclosed e.g. in Japanese Laid-Open Patent Publication (Kokai) No. H09-319357. The opening and closing device is comprised of a single rotary damper and a single link mechanism. The rotary damper is configured to cause the rotor to generate a braking force irrespective of the direction of rotation of the rotor, and the braking force is set to be larger in the clockwise rotation of the rotor than in the counterclockwise rotation of the same. The link mechanism is configured to transmit the pivotal motion of the fallboard to the rotary damper as well as to transmit the braking force of the rotary dumper to the fallboard. When the fallboard pivotally moves from a predetermined position between the fully closed position and the fully open position toward the fully open position, and when the fallboard rotates from the predetermined position toward the fully closed position, the rotor is caused to perform clockwise rotation by transmission of the pivotal motion of the fallboard via the link mechanism, and in the other cases, the rotor rotates in the counterclockwise direction.
As a consequence, in the conventional opening and closing device, when the fallboard pivotally moves from the predetermined position toward the fully open position or from the predetermined position toward the fully closed position, the rotary damper transmits a larger braking force to the fallboard via the link mechanism than in the other cases. This makes it possible to prevent the fallboard from strongly colliding against the upper panel of the keyboard instrument when the fallboard is opened or from colliding against the keyslip of the keyboard instrument when the fallboard is closed.
However, since the conventional opening and closing device uses only the single rotary damper as described above, it is impossible to sufficiently brake the fallboard immediately before the fallboard is fully opened or closed, and therefore there still is a fear that the fallboard strongly collides against the upper panel of the keyboard instrument when the fallboard is opened or strongly collides against the keyslip of the keyboard instrument when the fallboard is closed. Further, at an initial stage of the opening or closing operation of the fallboard as well, the braking force of the rotary damper acts on the fallboard, which can hinder smooth opening or closing operation of the fallboard.